This invention relates to a method of cleaning a carbon member contaminated with deposits of metals and/or metal compounds without adversely affecting the carbon body by using a cleaning gas containing a halogen compound gas. The carbon member itself is not limited and, for example, may be a graphite part of an apparatus for forming thin films in the manufacture of semiconductor devices.
In conventional processes for forming thin films for semiconductor devices such as PVD, CVD, vacuum evaporation and epitaxy processes it is almost inevitable that various parts of the apparatus and jigs are contaminated by the deposition of metals and/or some metal compounds such as carbides or nitrides. Therefore, it is necessary to periodically clean the contaminated parts by removing the deposits. For this purpose, conventional cleaning methods include chemical cleaning methods using a strong acid or a strong alkali, mechanical cleaning methods by grinding or the like and plasma etching methods using a fluorine compound gas such as CF.sub.4, SF.sub.6 or NF.sub.3.
However, the conventional cleaning methods involve various problems. In the case of cleaning with a strong acid or a strong alkali the cleaning operation is troublesome, and it is necessary to interrupt the operation of the apparatus for a relatively long period of time, and the parts or jigs subjected to cleaning are liable to be damaged. Mecanical cleaning methods such as grinding have similar disadvantages. In the case of cleaning by plasma etching using a fluorine compound as the etching gas the need of producing a plasma atmosphere places strict restrictions on the cleaning apparatus. Besides, when the parts to be cleaned are made of graphite or carbon in different form there occurs vigorous fluorination reaction between carbon and fluorine radical generated in the plasma atmosphere, so that the etching of the deposits is accompanied by erosion of the carbon surfaces.